Comparative genomic analysis of Bordetella bronchiseptica isolates from the lungs of pigs with porcine respiratory disease complex (PRDC)

Antimicrobial Resistance and Biofilm Formation of Bordetella bronchiseptica in Central China, with Evidence of a Rare Heteroresistance Strain to Gentamicin

Bordetella bronchiseptica is a significant contributor to respiratory disease in pigs, leading to substantial economic losses in the swine industry worldwide. We isolated 52 B. bronchiseptica strains from 542 samples collected from pigs with atrophic rhinitis and bronchopneumonia in central China. Multi-locus sequence typing identified two prevalent sequence types: ST6 (69.23%) and ST7 (30.77%). PCR-based detection of seven virulence genes (fhaB, prn, cyaA, dnt, bteA, fla, and bfrZ) revealed that six of these genes were present in over 90% of the isolates, with bfrZ being the exception at 59.62%. Antimicrobial susceptibility testing, performed using the K-B method, demonstrated high sensitivity to enrofloxacin, polymyxin, and doxycycline but a notable resistance to tylosin, trimethoprim, tobramycin, ciprofloxacin, and amikacin. Remarkably, 86.54% of the isolates exhibited a multidrug-resistant phenotype. Notably, we successfully screened a strain of B. bronchiseptica with a heteroresistance phenotype to gentamicin using population analysis profiling, which is a rare case. Biofilm-formation assays indicated that 96.15% of the isolates possessed biofilm-forming capabilities. These findings provide crucial insights into the prevalence of B. bronchiseptica in central China, facilitating the development of effective preventive measures to safeguard both animal and human health.

Anti-Bordetella bronchiseptica effects of targeted bacteriophages via microbiome and metabolic mediated mechanisms

Bordetella bronchiseptica poses a significant challenge in the context of respiratory infections, particularly in weanling pigs. In this study, we investigated the impact of a novel targeted bacteriophage in controlling B. bronchiseptica challenge (BBC) in an experimental design involving five distinct treatment groups: NC (no challenge), PC (BBC challenge), BF (108 pfu bacteriophage/kg diet + BBC), BN (2 × 107 pfu/day bacteriophage by nasal spray + BBC), and AT (antibiotic + BBC). The experiment was conducted for 2 weeks. The highest turbinate score was observed in the PC. The BF treatment showed higher plasma IL (interleukine)-1β and IL-6 compared with the BN and AT treatments. Plasma concentrations of IL-1β were increased in the BF pigs compared with the BN, AT, and NC. Among the BBC groups, the PC treatment exhibited a higher abundance of Staphylococcus. aureus and B. bronchiseptica in the lung. A lower S. aureus, Streptococcus. suis, and B. bronchiseptica colonization was detected in the AT compared with the BF and BN treatments. The BF showed lower plasma zonulin compared with the BN and AT. A higher plasma concentration of superoxide dismutase was observed in the BF and AT compared with PC and BN. The BN influenced the glycine, serine-threonine metabolism; glycerolipid metabolism; glyoxylate-dicarboxylate metabolism; and arachidonic acid metabolism compared with the NC. In conclusion, nasal-sprayed bacteriophage effectively controlled B. bronchiseptica infection, however, their efficiency was lower than the antibiotic.

Mechanism of gastrointestinal adaptability and antioxidant function of infant-derived Lactobacillus plantarum BF_15 through genomics

Lactobacillus plantarum is an essential probiotic in the human gastrointestinal tract. L. plantarum BF_15, a functional probiotic isolated from the feces of breast-fed infants, has been reported in many in vitro and in vivo studies with strong gastrointestinal adaptability and outstanding anti-oxidative activities. Therefore, the whole genome of L. plantarum BF_15 was sequenced. Several genes, encoding the gastrointestinal adaptability-related proteins, were identified, including genes related to gastrointestinal environment-induced stress resistance, adhesive performance, and ability to transport and metabolize resistant starch and oligosaccharides. Genes related to alleviating oxidative stress were also found. Further functional verification was carried out by RT-qPCR on the 10 and 12 key adhesion and antioxidant genes. Overall, this study might provide a critical basis for L. plantarum BF_15 as a potential candidate for probiotics.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-022-01132-w.

Genomic, morphological, and biochemical analyses of a multi-metal resistant but multi-drug susceptible strain of Bordetella petrii from hospital soil

Contamination of soil by antibiotics and heavy metals originating from hospital facilities has emerged as a major cause for the development of resistant microbes. We collected soil samples surrounding a hospital effluent and measured the resistance of bacterial isolates against multiple antibiotics and heavy metals. One strain BMCSI 3 was found to be sensitive to all tested antibiotics. However, it was resistant to many heavy metals and metalloids like cadmium, chromium, copper, mercury, arsenic, and others. This strain was motile and potentially spore-forming. Whole-genome shotgun assembly of BMCSI 3 produced 4.95 Mb genome with 4,638 protein-coding genes. The taxonomic and phylogenetic analysis revealed it, to be a Bordetella petrii strain. Multiple genomic islands carrying mobile genetic elements; coding for heavy metal resistant genes, response regulators or transcription factors, transporters, and multi-drug efflux pumps were identified from the genome. A comparative genomic analysis of BMCSI 3 with annotated genomes of other free-living B. petrii revealed the presence of multiple transposable elements and several genes involved in stress response and metabolism. This study provides insights into how genomic reorganization and plasticity results in evolution of heavy metals resistance by acquiring genes from its natural environment.

Genomic and metabolic features of the Lactobacillus sakei JD10 revealed potential probiotic traits

Lactic acid bacteria that inhabit in the lung play important roles in maintaining the microbiome balance by interacting with the host immune system. Numerous metabolites (e.g., short chain fatty acids, bacteriocins, and hydrogen peroxide) produced by Lactobacillus sakei possess a special inhibitory spectrum against invading pathogens. In this research, the whole genome of L. sakei JD10 strain isolated from the porcine lung was sequenced and investigated. The whole size of the L. sakei JD10 chromosome was 1,989,921 bp, which encoded a total of 1951 predicted genes. Genome analyses revealed that many genes encoded carbohydrate-active enzymes (CAZymes) were predicted, which were responsible for the carbohydrate degradation and short chain fatty acids production. The metabolic profiles of short chain fatty acids in the L. sakei JD10 culture medium were measured by GC/TOFMS, and their regulatory effects on bacterial phagocytosis of RAW264.7 cells were also determined. The bacteriocin-producing genes of the L. sakei JD10 genome were also predicted, and a bacteriocin gene encoding carnocin was characterized and its molecular structure was analyzed. Two CRISPR-Cas system related genes were identified from the L. sakei JD10 genome, revealed that precise and efficient genome editing technologies could be applied for genetic engineering-manipulation. In all, investigation on the genomic features and metabolic features of L. sakei JD10 showed the potential probiotic traits to fight against pathogenic infection and regulate the host immune function.